The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also be inventions.
The World Wide Web (WWW) relies on cross-domain communication to create an interconnected system of independent web applications. For security reasons, web browsers isolate web applications from each other by encapsulating protocol scheme, Internet domain name, and port into an abstraction called the origin. For example, a web browser prevents attacker.com from accessing web resources owned by example.com, and vice versa, because these Internet domains have different origins. In many web applications, communication between related domains is a common use case, such as between example.com and its sub-domains order.example.com and payment.example.com. Since related domains have different origins, related domains require mechanisms such as hyper-text transfer protocol access control (CORS) and window.postMessage for sharing web resources and communicating. When these legacy mechanisms are not supported by legacy web browsers, developers have to resort to insecure communication techniques. Some web applications require a persistent and light-weight communication mechanism without the rigidness of legacy mechanisms.